【推荐1】The African elephant holds the record for sleeping the least among mammals — about two hours a day — but now, the elephant seal is giving its namespace a run for its money. Recent experiments on elephant seals showed the animals averaged only two hours of sleep per day during the seven months out of the year they spent at sea.

Jessie Kendall-Bar, a Ph. D. at the University of California, discovered elephant seals’ special ability. She found in the open ocean, elephant seals sleep less than two hours per day. While on land, they sleep more than 10 hours a day. “That’s really special,” she says. Previous observations had shown that elephant seals in the open ocean surface for a couple of minutes at a time. So scientists knew that they must be sleeping underwater. But they knew very little about it.

To find out more, Kendall-Bar developed a headcap to gather data about the animals’ brain waves, heart rates, dive (潜水) depths, and movements to determine when they were sleeping. She discovered that seals do not sleep in two-hour bursts. Instead, they take some “catnaps (小睡)” lasting less than 20 minutes each. Starting at the surface, adult seals take 10-minute dives at great depths, usually from 300 to 1,000 feet.

At this point, the animals enter the first stage of sleep, or slow-wave sleep. Then, they fall into REM sleep, when their bodies turn upside down. It seems REM sleep at great depths is risky because of the inability to escape at that moment. “It is just scary to imagine an animal doing this underwater in that state,” says study co-author Terrie Williams.

But what’s likely happening is that the seals are sleeping at great depths where their primary hunters — sharks and killer whales — hardly appear. “The elephant seal is basically using its ability to div e really deep as a protective mechanism (机制),” says Kendall-Bar. “It doesn’t have to keep one eye open or stay awake. It’s sleeping with its entire brain.”

【推荐2】As we all know, trees are always stationary: they stay more or less where you plant them, and no one worries about finding a tree wandering around a park or back yard.

However, there is one special exception, some say：the so called walking palm tree (棕榈树) was found in the rainforests of Central and South America. Many people believe it can really walk around. This is because of its unusual root system: while most trees have one trunk, the palm breaks into many smaller roots a few feet off the ground, giving it the appearance of many little legs.

The amazing walking ability of the palm tree has always been told by rainforest guides to tourists for years, and appears in many sources of documents as an amazing plant adaptation. As journalist Sherry Seethaler writes in her book Curious Folks Ask 2: “Screen writers searching for the perfect B-movie (小成本电影) plant hero could take inspiration from the walking palm, The tree slowly walks from shade to sunlight by growing new roots toward the light.”

A tree that walks in search of the sun is a fascinating, strange story. And it's not true either; the tree is real enough, but it doesn't walk. It sits where it began to grow, not moving except under the force of wind or an axe.

Biologist Gerardo Avalos is one of the world's top experts on the Socratea exorrhiza. His analysis of the plant and its roots shows that the walking tree can't walk because its roots don't move. A few roots on one side or another may die off, but the trunk itself remains, well, rooted to the spot.

“My paper proves that the belief of the walking palm is just a myth,” Avalos said. “Thinking that a palm tree could actually track the sunlight changes by moving slowly over the forest floor…is a myth that tourist guides find amusing to tell visitors to the rainforest.”

【推荐1】Chemical engineers at UNSW Sydney have found a way to make "green" ammonia (氨) from air, water and renewable electricity. In a paper published in Energy and Environmental Science, the authors say that ammonia synthesis (合成法) was one of the critical achievements of the 20^th century. When used in fusiliers that significantly increase the output of food crops, it enabled agriculture to sustain an ever-expanding global population.

But since the beginning of the 1900s when it was first employed, production of ammonia has been energy intensive- requiring temperatures higher than 400℃ and pressures greater than 200 atm-and all powered by fossil fuels. Dr. Emma Lovell, a co author on the paper from UNSW, says the traditional way to make ammonia- known as the Haber- Bosch process- is only cost-effective when it is produced on a massive scale due to the huge amounts of energy and expensive materials required and it produces more CO₂ than any other chemical-making reaction.

“In addition to the big carbon footprint left by the Haber Bosch process, having to produce millions of tons of ammonia in centralised locations means even more energy is required to transport it around the world, not to mention the risks that go with storing large amounts of it in the one place,” says Dr. Lovell. “And we saw tragically in Beirut recently how potentially dangerous storing ammonium nitrate (硝酸盐) can be. ”

Dr. Lovell and her colleagues therefore looked at how to produce it cheaply, on a smaller scale and using renewable energy. Their new production method does not rely on fossil fuel resources, nor give of CO₂.

“And once it becomes available commercially, the technology could be used to produce ammonia directly on site and on demand- farmers could even do this on location using our technology to make fertilisers- which means we negate the need for storage and transport There's a huge benefit to society as well as the health of the planet,”Dr. Lovell says.